The present invention relates to ganged mowing machines in general, and more specifically to a hydraulically driven, self-propelled, ganged mowing machine with a vertically adjustable mower platform for particular use in cutting or pruning nursery products, such as shrubs, bushes, and the like.
A number of ganged mowing machines have been proposed in the past. The majority of these machines have been directed towards cutting large expanses of grass upon golf courses, parks, large estates, and roadsides. Typically, these machines are intended to be towed by a tractor where a power-take-off unit from the tractor provides the power required to run the mowers. A typical example of a towed ganged mower is U.S. Pat. No. 5,069,022 entitled “Gang Mower Apparatus,” issued to Vandermark. This device features nine rotary mowers attached to a frame which is towed behind a tractor. The mowers are mechanically driven by means of shafts and belts via a mechanical power-take-off from the tractor. Each mower unit is liftable from a cutting position to a travel position via a hydraulic cylinder. By lifting the mower units during periods of travel between mowing sites, the trailer may be towed at a faster rate of speed than if the mower units were left in the cutting position. Hydraulic power to drive the lifting cylinders is provided via a fluid-power-take-off from the tractor. Each mower unit is designed to be independently movable with respect to the other mower units in order for each unit to more closely follow the terrain to be cut. The vertical height of the mowers with respect to the ground may be adjusted within a range of a few inches via an adjustable swivel wheel.
Ganged mowing machines of this type are unsuitable for the special needs of cutting nursery products. On a large expanse of lawn, a tractor may proceed directly in front of the mowers while cutting the grass without harming the lawn. This is not possible in a nursery setting as the tractor would crush the bushes and shrubs to be cut. In addition, towed mowers of the type discussed above have a limited vertical height adjustment. Typically, these mowers are designed to cut grass to a height of about one to three inches above the ground. While this is a desirable feature in cutting lawns, it is entirely unsuitable to cutting shrubs, bushes and other nursery products which often require trimming at a height within a range of two to three feet from the ground. Further, towed mowing machines typically suspend the mowers independently of each other so that the mower may closely follow the terrain. Again, while this feature is desirable in a grass cutting machine, it is undesirable in cutting nursery products. Nursery products are typically arranged in rows and are often potted. This arrangement renders independently suspended mowers impractical because the multiplicity of wheels and suspension members required would destroy or otherwise severely damage the nursery products.
Related machines such as “riding” lawn mowers are also known in the art. Some of these machines may incorporate more than one rotary mower blade. However, machines of this type suffer most of the same disadvantages associated with towed ganged mowers. What is needed therefore is a ganged mowing machine specifically developed for the needs of cutting or trimming nursery products. Ideally, such a machine would have a horizontal platform on which is mounted an array of ganged mowers. The platform should be comparatively wide so that the a large number of rows of nursery products may be cut or trimmed at one time. The mowing machine should have wheels only at the extreme ends of the platform to avoid trampling the shrubs, bushes, or plants to be cut. In addition, the mowing machine should be self-propelled to eliminate the need for a tractor. Further, the machine should be designed so that the mowers may adjust to a vertical height up to about three feet from the ground.